Portal:Cetaceans

The orca (Orcinus orca), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. It is the only extant species in the genus Orcinus and is recognizable by its black-and-white patterned body. A cosmopolitan species, they are found in diverse marine environments, from Arctic to Antarctic regions to tropical seas.

Orcas are apex predators with a diverse diet. Individual populations often specialize in particular types of prey. This includes a variety of fish, sharks, rays, and marine mammals such as seals and other dolphins and whales. They are highly social; some populations are composed of highly stable matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often specific to a particular group and passed along from generation to generation, are considered to be manifestations of animal culture. (Full article...)

Orcinus meyeri is a fossil species of Orcinus (killer whales) found in the Early Miocene deposits of southern Germany, known from two jaw fragments and 18 isolated teeth. It was originally described as Delphinus acutidens in 1859, but reclassified in 1873. Its validity is disputed, and it may be a synonymous with the ancient sperm whale Physeterula dubusi. It was found in the Alpine town of Stockach in the Molasse basin, which was a coastal area with strong tidal currents. (Full article...)

Janjucetus is an extinct genus of cetacean, and a basal baleen whale (Mysticeti), from the Late Oligocene around 25 million years ago (mya) off south-east Australia, containing one species J. hunderi. Unlike modern mysticetes, it possessed large teeth for gripping and shredding prey, and lacked baleen, and so was likely to have been a predator that captured large single prey animals rather than filter feeding. However, its teeth may have interlocked, much like those of the modern-day filter-feeding crabeater seal (Lobodon carcinophaga), which would have allowed some filter-feeding behaviour. Its hunting behaviour was probably similar to the modern-day leopard seal (Hydrurga leptonyx), probably eating large fish. Like baleen whales, Janjucetus could not echolocate; however, it did have unusually large eyes, and so probably had an acute sense of vision. The only specimen was found on the Jan Juc beach, where the remains of the extinct whales Mammalodon, Prosqualodon and Waipatia have also been discovered. (Full article...)

Pilot whales are cetaceans belonging to the genus Globicephala. The two extant species are the long-finned pilot whale (G. melas) and the short-finned pilot whale (G. macrorhynchus). The two are not readily distinguishable at sea, and analysis of the skulls is the best way to distinguish between the species. Between the two species, they range nearly worldwide, with long-finned pilot whales living in colder waters and short-finned pilot whales living in tropical and subtropical waters. Pilot whales are among the largest of the oceanic dolphins, exceeded in size only by the orca. They and other large members of the dolphin family are also known as blackfish.

Pilot whales feed primarily on squid, but will also hunt large demersal fish such as cod and turbot. They are highly social and may remain with their birth pod throughout their lifetime. Short-finned pilot whales are one of the few non-primate mammal species in which females go through menopause, and postreproductive females continue to contribute to their pod. Pilot whales are notorious for stranding themselves on beaches, but the reason behind this is not fully understood. Marine biologists have shed some light on the matter, suggesting that it is due to the mammals inner ear (their principal navigational sonar) being damaged from noise pollution in the ocean, such as from cargo ships or military exercises. The conservation status of short-finned and long-finned pilot whales has been determined to be least concern. (Full article...)

The blue whale (Balaenoptera musculus) is a marine mammal and a baleen whale. Reaching a maximum confirmed length of 29.9 m (98 ft) and weighing up to 199 t (196 long tons; 219 short tons), it is the largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and B. m. indica in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies.

In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. There is also evidence of year-round residencies, and partial or age/sex-based migration. Blue whales are filter feeders; their diet consists almost exclusively of krill. They are generally solitary or gather in small groups, and have no well-defined social structure other than mother–calf bonds. Blue whales vocalize, with a fundamental frequency ranging from 8 to 25 Hz; their vocalizations may vary by region, season, behavior, and time of day. Orcas are their only natural predators. (Full article...)

Porpoises (/ˈpɔːrpəsɪz/) are small dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins (e.g. Hector's dolphin) also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.

Porpoises range in size from the vaquita, at 1.4 metres (4 feet 7 inches) in length and 54 kilograms (119 pounds) in weight, to the Dall's porpoise, at 2.3 m (7 ft 7 in) and 220 kg (490 lb). Several species exhibit sexual dimorphism in that the females are larger than males. They have streamlined bodies and two limbs that are modified into flippers. Porpoises use echolocation as their primary sensory system. Some species are well adapted for diving to great depths. As all cetaceans, they have a layer of fat, or blubber, under the skin to keep them warm in cold water. (Full article...)

The narwhal (Monodon monoceros) is a species of toothed whale native to the Arctic. It is the only member of the genus Monodon and one of two living representatives of the family Monodontidae. The narwhal has a similar build to the closely related beluga whale, with which it overlaps in range and can interbreed. It is a stocky cetacean with a relatively blunt snout, a large melon, and a shallow ridge in place of a dorsal fin. Males of this species have a large 1.5–3.0 m (4 ft 11 in – 9 ft 10 in) long tusk, which is a left protruded canine thought to serve as a weapon or as a tool for feeding, attracting mates or sensing water salinity. Specially adapted slow-twitch muscles, along with the jointed neck vertebrae and shallow dorsal ridge allow for easy movement through the Arctic environment, where the narwhal spends extended periods at great depths.

The narwhal inhabits the Arctic waters of Canada, Greenland and Russia. Every year, it migrates to ice-free summering grounds, usually in shallow waters, and often returns to the same sites in subsequent years. Its diet mainly consists of polar and Arctic cod, Greenland halibut, cuttlefish, shrimp, and armhook squid. Plunging at depths of up to 2,370 m (7,780 ft), the narwhal is among the deepest-diving cetaceans. It travels in groups of three to eight, with aggregations of up to 1,000 occurring in the summer months. It mates in the offshore pack ice from March to May, and the young are born in July or August of the following year. When communicating, a variety of clicks, whistles and knocks are used. (Full article...)

Whaling in the Faroe Islands, or grindadráp (from the Faroese terms grindhvalur, meaning pilot whale, and dráp, meaning killing), is a type of drive hunting that involves herding various species of whales and dolphins, but primarily pilot whales, into shallow bays to be beached, killed, and butchered. Each year, an average of around 700 long-finned pilot whales and several hundred Atlantic white-sided dolphins are caught over the course of the hunt season during the summer.

The practice dates back to the 9th century, and many Faroe Islanders consider eating whales to be an important part of their history. Since 1948, the hunt has been regulated by the Faroese authorities, required its participants to be trained, involved modern boats and communications, and been supervised by police. (Full article...)

Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey whale). Odontocetes include the Monodontidae (belugas and narwhals), Physeteridae (the sperm whale), Kogiidae (the dwarf and pygmy sperm whale), and Ziphiidae (the beaked whales), as well as the six families of dolphins and porpoises which are not considered whales in the informal sense.

Whales are fully aquatic, open-ocean animals: they can feed, mate, give birth, suckle and raise their young at sea. Whales range in size from the 2.6 metres (8.5 ft) and 135 kilograms (298 lb) dwarf sperm whale to the 29.9 metres (98 ft) and 190 tonnes (210 short tons) blue whale, which is the largest known animal that has ever lived. The sperm whale is the largest toothed predator on Earth. Several whale species exhibit sexual dimorphism, in that the females are larger than males. (Full article...)

The sei whale (/seɪ/ SAY, Norwegian: [sæɪ]; Balaenoptera borealis) is a baleen whale. It is one of ten rorqual species, and the third-largest member after the blue and fin whales. It can grow to 19.5 m (64 ft) in length and weigh as much as 28 t (28 long tons; 31 short tons). Two subspecies are recognized: B. b. borealis and B. b. schlegelii. The whale's ventral surface has sporadic markings ranging from light grey to white, and its body is usually dark steel grey in colour. It is among the fastest of all cetaceans, and can reach speeds of up to 50 km/h (31 mph) over short distances. 

It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semi-enclosed bodies of water. The sei whale migrates annually from cool, subpolar waters in summer to temperate, subtropical waters in winter with a lifespan of 70 years. It is a filter feeder, with its diet consisting primarily of copepods, krill, and other zooplankton. It is typically solitary or can be found in groups numbering half a dozen. During the breeding period, a mating pair will remain together. Sei whale vocalizations usually lasts half a second, and occurs at 240–625 hertz. (Full article...)

Right whales are three species of large baleen whales of the genus Eubalaena: the North Atlantic right whale (E. glacialis), the North Pacific right whale (E. japonica) and the Southern right whale (E. australis). They are classified in the family Balaenidae with the bowhead whale. Right whales have rotund bodies with arching rostrums, V-shaped blowholes and dark gray or black skin. The most distinguishing feature of a right whale is the rough patches of skin on its head, which appear white due to parasitism by whale lice. Right whales are typically 13–17 m (43–56 ft) long and weigh up to 100 short tons (91 t; 89 long tons) or more.

All three species are migratory, moving seasonally to feed or give birth. The warm equatorial waters form a barrier that isolates the northern and southern species from one another although the southern species, at least, has been known to cross the equator. In the Northern Hemisphere, right whales tend to avoid open waters and stay close to peninsulas and bays and on continental shelves, as these areas offer greater shelter and an abundance of their preferred foods. In the Southern Hemisphere, right whales feed far offshore in summer, but a large portion of the population occur in near-shore waters in winter. Right whales feed mainly on copepods but also consume krill and pteropods. They may forage the surface, underwater or even the ocean bottom. During courtship, males gather into large groups to compete for a single female, suggesting that sperm competition is an important factor in mating behavior. Gestation tends to last a year, and calves are weaned at eight months old. (Full article...)

Whale barnacles are species of acorn barnacle that belong to the family Coronulidae. They typically attach to baleen whales, and sometimes settle on toothed whales. The whale barnacles diverged from the turtle barnacles about three million years ago.

Whale barnacles passively filter food, using tentacle-like cirri, as the host swims through the water. The arrangement is generally considered commensal as it is done at no cost or benefit to the host. However, some whales may make use of the barnacles as protective armor or for inflicting more damage while fighting, which would make the relationship mutualistic where both parties benefit; alternatively, some species may just increase the drag that the host experiences while swimming, making the barnacles parasites. (Full article...)

Rice's whale (Balaenoptera ricei), also known as the Gulf of Mexico whale, is a species of baleen whale endemic to the northern Gulf of Mexico. Initially identified as a subpopulation of the Bryde's whale, genetic and skeletal studies found it to be a distinct species by 2021. In outward appearance, it is virtually identical to the Bryde's whale. Its body is streamlined and sleek, with a uniformly dark charcoal gray dorsal and pale to pinkish underside. A diagnostic feature often used by field scientists to distinguish Rice's whales from whales other than the Bryde's whale is the three prominent ridges that line the top of its head. The species can be distinguished from the Bryde's whale by the shape of the nasal bones, which have wider gaps due to a unique wrapping by the frontal bones, its unique vocal repertoire, and genetic differences.

It is a medium-sized baleen whale that grows up to 12.65 meters (41.5 ft) in length and weighs up to 13.87–27.2 metric tons (13.65–26.77 long tons; 15.29–29.98 short tons). The Rice's whale inhabits a restricted stretch along the continental slope in the northeastern part of the Gulf of Mexico between depths of 150–410 meters (490–1,350 ft) off the coast of western Florida, although some whales have been sighted in the northwestern portions and the species may have inhabited a wider distribution throughout the Gulf in historical times. It does not migrate but remains within this area year-round. Little is known about the feeding behavior of Rice's whales, but data from a tagged individual revealed a diel vertical diving pattern, in which the whale spends most of the day feeding at or near the seafloor at depths of up to 271 meters (889 ft) and night at the surface. The whale's diet remains unknown, but lanternfish and hatchetfish are suspected prey. (Full article...)

Dolphin drive hunting, also called dolphin drive fishing, is a method of hunting dolphins and occasionally other small cetaceans by driving them together with boats, usually into a bay or onto a beach. Their escape is prevented by closing off the route to the open sea or ocean with boats and nets. Dolphins are hunted this way in several places around the world including the Solomon Islands, the Faroe Islands, Peru, and Japan, which is the most well-known practitioner of the method. In large numbers dolphins are mostly hunted for their meat; some end up in dolphinariums.

Despite the controversial nature of the hunt resulting in international criticism, and the possible health risk that the often polluted meat causes, tens of thousands of dolphins are caught in drive hunts each year. (Full article...)

The humpback whale (Megaptera novaeangliae) is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus Megaptera. Adults range in length from 14–17 m (46–56 ft) and weigh up to 40 metric tons (44 short tons). The humpback has a distinctive body shape, with long pectoral fins and tubercles on its head. It is known for breaching and other distinctive surface behaviors, making it popular with whale watchers. Males produce a complex song typically lasting 4 to 33 minutes.

Found in oceans and seas around the world, humpback whales typically migrate up to 16,000 km (9,900 mi) each year. They feed in polar waters and migrate to tropical or subtropical waters to breed and give birth. Their diet consists mostly of krill and small fish, and they use bubbles to catch prey. They are promiscuous breeders, with both sexes having multiple partners. Orcas are the main natural predators of humpback whales. (Full article...)